Some people promote theories and treatments that they claim to be scientific, but are not. On this website, we often refer to such dubious claims as “woo” or pseudoscience. These often troublesome theories and treatments are widely advertised on the internet, on TV, and in the psychology or self-help sections of commercial book stores. But because some material in these venues is legitimate, it is important to know how to distinguish science from pseudoscience.

Here we provide a useful toolkit which can be used to identify pseudoscience. The following warning signs are just a rough guide and should be used with some care, because the distinction between science and pseudoscience is rarely clear-cut. Nevertheless, the more warning signs, the more suspicious of a claim you should be.

Warning signs that something is not scientific:

It cannot be tested.

Pseudoscience is often either impossible to test or excuses are made which keep it from being tested.

In some cases, when evidence does not support the claim, instead of abandoning their ideas, pseudoscientists add conditions to their theories or explain away the evidence so that it is impossible to test the claim empirically. For example, a psychic who cannot demonstrate mind reading or other psychic feats under carefully controlled conditions in the laboratory might claim that “the skeptical vibes of experimenters” are blocking his or her psychic powers. Such an excuse makes the claim untestable.

In other cases, pseudoscientific theories cannot be tested right from the start.

The basic theory does not change in response to evidence.

Genuine science adapts and updates its theories in response to new evidence, especially refuting evidence. In contrast, pseudoscience tends to maintain its initial claims and instead dismisses or ignores counter-evidence.

The claimants avoid peer review or other outside verification.

Peer review is the checking of scientific-journal articles by other scientists. Although it is by no means perfect, peer review is an effective, if slow, safeguard against human error. Pseudoscientists tend to avoid close scrutiny. In many cases, their descriptions of procedures and mechanisms are vague and the terms they use are undefined (e.g., “energy”). In other cases they may claim that “orthodox science” conspires against them.

They only look for evidence which confirms their hypothesis.

In science, studies are designed to disprove hypotheses, not to confirm them. This is because confirming evidence cannot tell us if the hypothesis is always true or if we have simply not seen a case in which it is false. For example, we could test the hypothesis that all birds fly by dropping birds from a bridge. We would confirm our hypothesis many times over, but we would not discover that it was wrong unless we happened to drop a chicken, penguin, or ostrich.

Scientists look for evidence that their theories are false. Pseudoscientists, however, often look only for evidence which supports their beliefs.

The claimant insists that their theory is accurate because it has not been proven wrong.

Pseudoscientists typically say that it up to critics to disprove their claims, and until they do they should hold firmly to their beliefs. However, the burden of proof is on those making the claim.

The claim defies what established science has told us about the world.

Pseudoscientists often claim to have discovered a completely new way of looking at the world, one which requires existing scientific knowledge to be tossed out. For example, “psychic surgeons” claim to remove tumors from a patient’s abdomen without cutting the skin. This is considered an extraordinary claim as it defies the laws of nature as we know them. Such claims require extraordinary evidence.

The claimants attempt to persuade using anecdotes.

Pseudoscientists tend to rely on evidence that is testimonial – engaging and vivid personal stories. These stories are often touching and persuasive. Although such testimonies may be useful starting points in the early stages of scientific study, they rarely provide enough evidence to accept a claim. That’s because they are often difficult to verify, unrepresentative of people’s experiences, and open to alternative explanations that pseudoscientists haven’t considered.

The claimants use confusing and inappropriate scientific-sounding jargon to persuade.

Pseudoscientists sometimes use jargon which hides the lack of substance in their claims. Scientific or highly technical words are used to impress the reader and make it look like science. Technical or scientific terms are often used out of context. For example, the claim that a product regulates the flow of ions in the body is a misuse of the term “ion”, which refers to states of a molecule, not something that flows in the body.

The claim has no limits.

In science, theories are specific and treatments have limits. In contrast, pseudoscientists often claim that their theory or treatment applies to just about everything. For example, sham treatments for ADHD also claim to treat or even cure autism, learning disabilities, and other behavioral disorders even though these disorders are completely different in nature and have different causes.

The claimant rejects counter-evidence from specific testing because it is not “holistic”.

“Holistic” is often used to mean “treating the whole person.” Buyer-beware if “holistic” is used in such a way as to explain away unfavorable results, or to undermine the value of testing specific parts of the treatment or theory.

“For example, the claim that a product regulates the flow of ions in the body is a misuse of the term ‘ion’, which refers to states of a molecule, not something that flows in the body.”

That’s not a good example of misuse of scientific terms. First, an ion can be a molecule or an an atom with an excess or deficit of electrons. Second, ions are particles, and particles are quite capable of flowing, especially if you are talking about large numbers of them. It wouldn’t be ridiculous at all to speak of sodium ions flowing across the membranes of nerve cells. In the stomach, hydrogen and chloride ions flow around quite a bit, especially after meal times; they’re what’s in stomach acid (HCl).

Of course, if someone is selling a product that supposedly “regulates the flow of ions” in general, one is making a uselessly vague claim about the product and is also probably a quack trying to dazzle customers with the word “ion.” I’m sure that’s what you were trying to get at.

I think the flow of ions has been used incorrectly in some specific cases of pseudoscience, so I understand why the example might be used to demonstrate the misuse of sceintific terms.
I think another example, J.J., might to be more to your liking. The term “quantum” has been taken out of context of quantum mechanics and misused to apply to consciousness and creativity (for example by Deepak Chopra). Now, I’m not niave to the fact that some people would disagree with this, but because quantum mechanics applies within strict boundary conditions, I think that using “quantum” in popular books on consciousness or creativity misleads and confuses the public.

Lawrence, I doubt that most scientist would object to “quantum” as an example of a misused term and Chopra certainly misuses it often. The problem is that explaining why it is misused is not a simple task, nor a short one.

A related problem that is a little easier to explain is when people use terms which are not scientific, but sound as if they are, like “bio-electric” or “aqua-titanium”.

There is a large amount of philosophical literature regarding the “demarcation problem” with regards to science vs pseudoscience. Some genuine science can meet some of the above criteria. And, many have characterized pseudoscience in various ways. It’s not so clear cut. I just delved into this recently after not really grasping it after 15 years of reading skeptical literature (maybe I was just a bit too casual about it). Another important aspect of “pseudoscience” is its social aspect – it’s a derogatory term. No one ever claims to be “pseudoscientific”; it’s a label foisted onto a field or subject by those who regard it as illegitimate. In this sense, it’s a way for sciences to close rank and reject a challenge. So, some have said it shouldn’t be used. I say it’s a useful term especially for the public because it does indicate questionable scientific legitimacy and OUGHT TO BE a red flag for people to look more closely.

Yes, I’ve also heard the arguments against the use of the word pseudoscience, or even demarcation criteria. Kuhn, for example, did not see things like Popper in any way at all; although Kuhn in 1977 did give some guidance as to what may be a good scientific theory.
I think one approach which I have some sympathy with is to focus on the evidence, rather than demarcation criteria. I think Richard McNally said somthing to that effect, and in some cases that may be true.
However, demarcation criteria have proven useful to help people escape from healing cults or expensive and wierd pseudoscientific treatments.
Intrinsic in the demarcation criteria is some teaching about what science is, or what it should be, which is important information that can lead to “aha” moments for those who have been scammed by pseudoscience.
I agree with you that it pseudoscience a useful concept, and those of us that continue to use the term understand and reject the call to stop using it, and that rejection is not from a shallow reading of the philosophy of science.

It comes down to the human aspects. Pseudoscience comes from people someone who dissemble their own doubts and lack of knowledge. They are like that guy on a trip who can’t read a map to save his life but keeps telling everyone that he knows exactly where they are at. Science is merely the ability to admit when one is wrong or isn’t sure. No legitimate pursuit of truth will ever rely on dishonesty as a valid means of convincing others to believe in something. That’s why science is the only legitimate method by which to pursue truth.

Science and Earth History by Arthur N. Strahler describes the differences between science and pseudoscience in great detail. A quite enjoyable read and a very entertaining (albeit slightly dated)refutation of creationism.

[...] around’ this post for the last couple of months on and off and just today (28th June 2010) found this nice post on ‘Woo Fighters‘ via Research Blogging Psychology and based on [4]. In this case both [...]

Recently I told someone: The existence of something contingent needs by force the previous existence of something absolutely necessary. Only something everlasting can explain that contingent. I got from him this answer: That is not science, because you can not prove it. Human reason is not enough to prove something.
Readers: What do you think about it?

I am not sure what you are asking, but if you are arguing about it, neither has defined science correctly.

Statements are not science. Science is a process of acquiring knowledge which uses observation and logic. What you’ve done is make a few assertions and, frankly, none of them make sense to me.

In response to your friend, he/she is partly correct, but not entirely.

1 – There is no such thing as proof because there are things we cannot be certain of; we must accept a set of first principles – inductively reasoned – as true in order to learn anything about the world. If they are not, then every argument which rests on them is questionable.
2 – Science cannot prove, nor is that its goal.
3 – Reason is not enough to know anything, either. You must also start with true premises. For example, take the argument: All dogs have four legs and Daisy is a dog, therefore Daisy has four legs. It’s perfectly valid; the reasoning is solid. However, the premise “all dogs have four legs” is not true. The conclusion is therefore unsupported.

I agree with Barbara, and I would like to also pick up on Juan’s comment “human reason is not enough to prove something.” I completely agree with this, although when I was studying math and physics I didn’t. Since switching to psychology, I eventually have become more aware of the importance of evidence (rather than deriving things from first principles, or from reason). I have known more than a couple clinical psychologists who do not understand that, and they drifted into pseudoscience: by coming up with theories not based in evidence, that lack falsifiability, but that explain everything to them. The importance of evidence and testibility should be constantly taught to students.

My friend says: Perelman tries to prove mathematically God’s existence. I say: Why mathematically? Human reason is enough. If by definition God is that absolutely necessary to explain that contingent, then God exists. That contingent is obvious. In no way could exist that contingent without something necessary previous. From Nothingness to Somethingness the leap is impossible -says human reason. You cannot test this proposition in a laboratory, since you cannot reproduce Nothingness at will and then see what happens. So you must by force rely on human mind and reason to prove God’s existence and Mathematics are not required. Otherwise to talk about proving God’s existence has no sense.

And I highly recommend that you visit a forum – a place which is designed for discussions like these. You’ll find people willing to discuss your interests. This is the comment section of a blog post and it is not designed for lengthy discussion. Perhaps the JREF forum at randi.org?

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